The company, which delivers food for 25,000 UK restaurants, said it's "had an excellent start to 2016."

The London Stock Exchange-listed company is now expecting full year sales to climb to £358 million instead of £350 million, and full-year earnings before interest and tax to come in at £102 million - £104 million, as opposed to the £98 million to £100 million originally forecast.

"We have had an excellent start to 2016 and I am delighted with the company's performance and the momentum in the business," said JustEat chief executive David Buttress, in a statement. "The team has continued to work hard to deliver increased value and ever more orders to our restaurant partners. Our focused strategy and improvements to both our consumer offering and restaurant support are working and we are well positioned to continue benefitting from channel shift in the category."

Analysts at Edison Investment Research warned in March that many of the latest food delivery startups are turning out to be "donkeys not unicorns."

But Saul Klein, the cofounder of the LocalGlobe venture capital fund and a former partner at Index Ventures, told Business Insider last month that JustEat has proven food delivery companies can succeed.

"It started off being a brilliant business in Denmark," he said, adding that the company has very strong business fundamentals. "Ben [Holmes], my partner at Index, invested in it. It's extremely successful in the UK and many other markets."